1. Field of the Invention
The present invention relates to a computer network for information processing devices, and more particularly to a network configuration in which an IP address can be assigned without installing a DHCP server and without necessity of registering in advance the information processing devices connected to the network.
2. Description of Related Art
In recent years, an information processing device, such as a computer or a workstation, may be connected to various kinds of networks, including the Internet, a local area network (LAN), or a wide area network (WAN). In these networks, the software and hardware resources may be shared electronically. For example, shared software resources may include various kinds of data. Likewise, shared hardware resources may include storage devices, printers, and many other network resources. Each information processing device connected to one of these networks typically must be uniquely identified from the other information processing devices connected to the network. At present, an information processing device is typically identified using a unique Internet Protocol (IP) address assigned to each information processing device.
FIG. 15 shows a characteristic network system that uses IP addresses for interconnecting multiple information processing devices. The conventional network system employs a Bootstrap Protocol (BOOTP) on the User Datagram Protocol/Internet Protocol (UDP/IP). The illustrated information processing devices include a server computer 102 and a client computer 104, each connected to the network 100.
The depicted network 100 is further connected to another network 108, such as the Internet, using a router 106. Also, the server computer 102 and the client computer 104 are interconnected via a network interface card (NIC) 110, such as a network card or a network board that enables electronic communication through over the network 100.
The network 100 using the BOOTP as shown in FIG. 15 assigns an IP address to the client computer 104, employing a broadcast communication when starting a diskless client computer 104. The IP address is previously known to the server computer 102. After the IP address is assigned to the client computer 104, an operating system is transferred from the server computer 102 to the client computer 104 to enable the operation of the client computer 104. The detailed specifications of this BOOTP are defined in RFC951-BOOTSTRAP PROTCOL (BOOTP).
FIG. 16 is a diagram showing a typical network system in which the IP address is assigned using a Dynamic Host Configuration Protocol (DHCP) server 114. In this network system, the server computer 102 and the client computer 104 are connected to the network 100. Additionally, a DHCP server 114 is connected to the network 100. In a manner similar to that described above, the client computer 104 may acquire an IP address from the DHCP server 114. For example, the client computer 104 may make a connection with the DHCP server 114 through a broadcast communication to acquire the IP address. At the same time, the client computer 104 may also acquire a gateway address, a domain name, and a subnet mask from the DHCP server 114
A typical DHCP server 114 has a range of assignable IP addresses that are registered to the network 100. In one instance, the network 100 is managed by the DHCP server 114 in that the DHCP server 114 enables the client computer 104 to have an assigned IP address and acquire other information through the broadcast communication. For example, the DHCP server 114 may receive an IP address request from the client computer 104 with the IP address unassigned through the broadcast communication. The DHCP server 114, having received the IP address request, selects an unused IP address, and transmits the IP address to the client computer 104. The client computer 104 is in this way assigned the IP address within the network environment. The industry standards for a typical DHCP server 114 are defined in detail in RFC 2131-Dynamic Host Configuration Protocol, RFC 2132-DHCP options, and BOOTP Vendor Extensions.
As described above, using a DHCP server 114 to centrally manage the assignment of network IP addresses can be very effective. One obvious drawback, however, is the need for DHCP server. Furthermore, in a network system that includes one or more appliance servers, the IP address of the appliance server is changed when a lease period has elapsed by assigning the IP address using the DHCP server in rebooting the appliance server. Although a DHCP server function may be added to the appliance server, software for switching the DHCP server must be added during server downtime. In this way, it is often inappropriate to assign the IP address using the DHCP server function in the network for managing the appliance server.
In addition, the Pre-Boot Execution Environment (PXE) standards and an Automatic Private IP Addressing (APIPA) technique are utilized in recent years, thereby enabling the IP address to be assigned to the information processing device connected to the network. Though not the IP base, the Network Basic Input Output System (NetBIOS) for displaying a name list of information processing devices by registering the names of information processing devices in advance is well known. A similar function can be also used in the NetBIOS over Transmission Control Protocol/Internet Protocol (TCP/IP). However, the information processing device displaying the list must have the IP address already assigned, but the NetBIOS over TCP/IP can not be used to assign the IP address to the information processing device.
What is needed is a manner of assigning an IP address to an information processing device without relying on a DHCP server and further without applying an excessive load on the server for providing the application. Beneficially, such a method would not require a DHCP server and would allow the network to be easily reconfigured.